Positive psychology is "the scientific study of what makes life most worth living", or "the scientific study of positive human functioning and flourishing on multiple levels that include the biological, personal, relational, institutional, cultural, and global dimensions of life". Positive psychology is concerned with eudaimonia, "the good life", reflection about what holds the greatest value in life - the factors that contribute the most to a well-lived and fulfilling life.
Positive psychology began as a new domain of psychology in 1998 when Martin Seligman chose it as the theme for his term as president of the American Psychological Association.Mihaly Csikszentmihalyi and Christopher Peterson are regarded as co-initiators of this development. It is a reaction against psycho-analysis and behaviorism, which have focused on "mental illness", meanwhile emphasising maladaptive behavior and negative thinking. It builds further on the humanistic movement, which encouraged an emphasis on happiness, well-being, and positivity, thus creating the foundation for what is now known as positive psychology.
Guiding theories are Seligman's P.E.R.M.A., and Csikszentmihalyi's theory of flow, while Seligman and Peterson's Character Strengths and Virtues was a major contribution to the methodological study of positive psychology.
Positive psychologists have suggested a number of ways in which individual happiness may be fostered. Social ties with a spouse, family, friends and wider networks through work, clubs or social organisations are of particular importance, while physical exercise and the practice of meditation may also contribute to happiness. Happiness may rise with increasing financial income, though it may plateau or even fall when no further gains are made.
Seligman and Csikszentmihalyi define positive psychology as:
... the scientific study of positive human functioning and flourishing on multiple levels that include the biological, personal, relational, institutional, cultural, and global dimensions of life.
Christopher Peterson defines positive psychology as:
...the scientific study of what makes life most worth living,"
Positive psychology is concerned with eudaimonia, "the good life" or flourishing, living according to what holds the greatest value in life - the factors that contribute the most to a well-lived and fulfilling life. While not attempting a strict definition of the good life, positive psychologists agree that one must live a happy, engaged, and meaningful life in order to experience "the good life". Martin Seligman referred to "the good life" as "using your signature strengths every day to produce authentic happiness and abundant gratification". According to Christopher Peterson, "eudaimonia trumps hedonism".
According to Seligman and Peterson, positive psychology is concerned with three issues: positive emotions, positive individual traits, and positive institutions. Positive emotions are concerned with being content with one's past, being happy in the present and having hope for the future. Positive individual traits focus on one's strengths and virtues. Finally, positive institutions are based on strengths to better a community of people.
According to Peterson, positive psychologists are concerned with four topics: (1) positive experiences, (2) enduring psychological traits, (3) positive relationships, and (4) positive institutions. According to Peterson, topics of interest to researchers in the field are: states of pleasure or flow, values, strengths, virtues, talents, as well as the ways that these can be promoted by social systems and institutions.
Positive psychology complements, without intending to replace or ignore, the traditional areas of psychology. By emphasizing the study of positive human development this field helps to balance other approaches that focus on disorder, and which may produce only limited understanding. Positive psychology has also placed a significant emphasis on fostering positive self-esteem and self-image, though positive psychologists with a less humanist bent are less likely to focus as intently on the matter. 
The basic premise of positive psychology is that human beings are often drawn by the future more than they are driven by the past. A change in our orientation to time can dramatically affect how we think about the nature of happiness. Seligman identified other possible goals: families and schools that allow children to grow, workplaces that aim for satisfaction and high productivity, and teaching others about positive psychology.
Those who practice positive psychology attempt psychological interventions that foster positive attitudes toward one's subjective experiences, individual traits, and life events. The goal is to minimize pathological thoughts that may arise in a hopeless mindset, and to, instead, develop a sense of optimism toward life. Positive psychologists seek to encourage acceptance of one's past, excitement and optimism about one's future experiences, and a sense of contentment and well-being in the present.
Positive psychology began as a new area of psychology in 1998 when Martin Seligman chose it as the theme for his term as president of the American Psychological Association. In the first sentence of his book Authentic Happiness, Seligman claimed: "for the last half century psychology has been consumed with a single topic only - mental illness",:xi expanding on Maslow's comments. He urged psychologists to continue the earlier missions of psychology of nurturing talent and improving normal life.
The term originates with Maslow, in his 1954 book Motivation and Personality, and there have been indications that psychologists since the 1950s have been increasingly focused on the promotion of mental health rather than merely treating mental illness.
The first positive psychology summit took place in 1999. The First International Conference on Positive Psychology took place in 2002. More attention was given by the general public in 2006 when, using the same framework, a course at Harvard University became particularly popular. In June 2009, the First World Congress on Positive Psychology took place at the University of Pennsylvania.
The International Positive Psychology Association (IPPA) is a recently established association that has expanded to thousands of members from 80 different countries. The IPPA's missions include: (1) "further the science of positive psychology across the globe and to ensure that the field continues to rest on this science" (2) "work for the effective and responsible application of positive psychology in diverse areas such as organizational psychology, counselling and clinical psychology, business, health, education, and coaching", (3) "foster education and training in the field".
The field of positive psychology today is most advanced in the United States and Western Europe. Even though positive psychology offers a new approach to the study of positive emotions and behavior, the ideas, theories, research, and motivation to study the positive side of human behavior is as old as humanity.
Several humanistic psychologists, most notably Abraham Maslow, Carl Rogers, and Erich Fromm, developed theories and practices pertaining to human happiness and flourishing. More recently, positive psychologists have found empirical support for the humanistic theories of flourishing. In addition, positive psychology has moved ahead in a variety of new directions.
In 1984, Diener published his tripartite model of subjective well-being, positing "three distinct but often related components of wellbeing: frequent positive affect, infrequent negative affect, and cognitive evaluations such as life satisfaction". In this model, cognitive, affective and contextual factors contribute to subjective well-being. According to Diener and Suh, subjective well-being is "...based on the idea that how each person thinks and feels about his or her life is important".
Carol Ryff's Six-factor Model of Psychological Well-being was initially published in 1989, and additional testing of its factors was published in 1995. It postulates six factors which are key for well-being, namely self-acceptance, personal growth, purpose in life, environmental mastery, autonomy, and positive relations with others.
According to Corey Keyes, who collaborated with Carol Ryff and uses the term flourishing as a central concept, mental well-being has three components, namely hedonic (c.q. subjective or emotional), psychological, and social well-being. Hedonic well-being concerns emotional aspects of well-being, whereas psychological and social well-being, c.q eudaimonic well-being, concerns skills, abilities, and optimal functioning. This tripartite model of mental well-being has received extensive empirical support across cultures.
There is no accepted "gold standard" theory in positive psychology, however the work of Seligman is regularly quoted. So too the work of Csikszentmihalyi and older models of well-being, such as Carol Ryff's Six-factor Model of Psychological Well-being and Diener's tripartite model of subjective well-being.
These categories appear neither widely disputed nor adopted by researchers across the years that this academic area has been in existence.
In Flourish (2011) Seligman argued that the last category, "meaningful life", can be considered as 3 different categories. The resulting acronym is PERMA: Positive Emotions, Engagement, Relationships, Meaning and purpose, and Accomplishments. It is a mnemonic for the five elements of Martin Seligman's well-being theory:
Each of the five PERMA elements was selected according to three criteria:
The development of the Character Strengths and Virtues (CSV) handbook (2004) represented the first attempt by Seligman and Peterson to identify and classify positive psychological traits of human beings. Much like the Diagnostic and Statistical Manual of Mental Disorders (DSM) of general psychology, the CSV provided a theoretical framework to assist in understanding strengths and virtues and for developing practical applications for positive psychology. This manual identified 6 classes of virtues (i.e., "core virtues"), underlying 24 measurable character strengths.
The CSV suggested these 6 virtues have a historical basis in the vast majority of cultures; in addition, these virtues and strengths can lead to increased happiness when built upon. Notwithstanding numerous cautions and caveats, this suggestion of universality hints threefold: 1. The study of positive human qualities broadens the scope of psychological research to include mental wellness, 2. the leaders of the positive psychology movement are challenging moral relativism, suggesting people are "evolutionarily predisposed" toward certain virtues, and 3. virtue has a biological basis.:51
The organization of the 6 virtues and 24 strengths is as follows:
Recent research challenged the need for 6 virtues. Instead, researchers suggested the 24 strengths are more accurately grouped into just 3 or 4 categories: Intellectual Strengths, Interpersonal Strengths, and Temperance Strengths or alternatively, Interpersonal Strengths, Fortitude, Vitality, and Cautiousness These strengths, and their classifications, have emerged independently elsewhere in literature on values. Paul Thagard described examples; these included Jeff Shrager's workshops to discover the habits of highly creative people. Some research indicates that well-being effects that appear to be due to spirituality are actually better described as due to virtue.
In the 1970s Csikszentmihalyi's began studying flow, a state of absorption where one's abilities are well-matched to the demands at-hand. Flow is characterized by intense concentration, loss of self-awareness, a feeling of being perfectly challenged (neither bored nor overwhelmed), and a sense that "time is flying". Flow is intrinsically rewarding; it can also assist in the achievement of goals (e.g., winning a game) or improving skills (e.g., becoming a better chess player). Anyone can experience flow, in different domains, such as play, creativity, and work. Flow is achieved when the challenge of the situation meets one's personal abilities. A mismatch of challenge for someone of low skills results in a state of anxiety; insufficient challenge for someone highly skilled results in boredom.
Research in positive psychology, well-being, eudaimonia and happiness, and the theories of Diener, Ryff, Keyes and Seligman cover a broad range of topics including "the biological, personal, relational, institutional, cultural, and global dimensions of life".  A meta-analysis on 49 studies in 2009 showed that Positive Psychology Interventions (PPI) produced improvements in well-being and lower depression levels, the PPIs studied included writing gratitude letters, learning optimistic thinking, replaying positive life experiences and socializing with others. In a later meta-analysis of 39 studies with 6,139 participants in 2012, the outcomes were positive. Three to six months after a PPI the effects for subjective well-being and psychological well-being were still significant. However the positive effect was weaker than in the 2009 meta analysis, the authors concluded that this was because they only used higher quality studies. The PPIs they considered included counting blessings, kindness practices, making personal goals, showing gratitude and focusing on personal strengths.
Ilona Boniwell, in her book Positive Psychology in a Nutshell, provided the following summary of the current research. Wellbeing is related to optimism, extraversion, social connections (i.e. close friendships), being married, having engaging work, religion or spirituality, leisure, good sleep and exercise, social class (through lifestyle differences and better coping methods) and subjective health (what you think about your health). Wellbeing is not related to age, physical attractiveness, money (once basic needs are met), gender (women are more often depressed but also more often joyful), educational level, having children (although they add meaning to life), moving to a sunnier climate, crime prevention, housing and objective health (what doctors say).
Sonja Lyubomirsky, in her book The How Of Happiness, says that to improve happiness individuals should create new habits; they can seek out new emotions, use variety and timing to prevent hedonic adaptation and enlist others to motivate and support during the creation of those new habits. Lyubomirsky gives 12 happiness activities such as savouring life, learning to forgive and living in the present, each of which could become the basis for a new habit.
In Positive Psychology The Science Of Happiness, the authors Compton and Hoffman give the "Top Down Predictors" of wellbeing as high self esteem, optimism, self efficacy, a sense of meaning in life and positive relationships with others. The personality traits most associated with well being are extraversion, agreeability and low levels of neuroticism.
In the Journal of Occupational Rehabilitation, Kreutzer and Mills argue for the principles of positive psychology to be implemented to assist those recovering from Traumatic Brain Injury(TBR). They make the case that TBI rehabilitation practices rely on the betterment of the individual through engaging in everyday practices, a practice significantly related to tenants of positive psychology. Their proposal to connect positive psychology with TBI Vocational Rehabilitation(VR)also looks at happiness and its correlation with improvements in mental health, including increased confidence and productivity, as well as others. While the authors point out that empirical evidence for positive psychology is limited, they clarify that positive psychology's focus on small successes, optimism and prosocial behaviour is promising for improvements in the social and emotional well-being of TBI patients.
According to Kirk Schneider, positive psychology fails to explain past heinous behaviors such as those perpetrated by the Nazi party, Stalinist marches and Klan gatherings, to identify but a few. Furthermore, Schneider pointed to a body of research showing high positivity correlates with positive illusion, which effectively distorts reality. The extent of the downfall of high positivity (also known as flourishing) is one could become incapable of psychological growth, unable to self-reflect, and tend to hold racial biases. By contrast, negativity, sometimes evidenced in mild to moderate depression, is correlated with less distortion of reality. Therefore, negativity might play an important role within the dynamics of human flourishing. To illustrate, conflict engagement and acknowledgement of appropriate negativity, including certain negative emotions like guilt, might better promote flourishing. Overall, Schneider provided perspective: "perhaps genuine happiness is not something you aim at, but is a by-product of a life well lived, and a life well lived does not settle on the programmed or neatly calibrated". Seligman has acknowledged in his work the point about positive illusion, and is also a critic of merely feeling good about oneself apart from reality and recognises the importance of negativity / dysphoria.
Ian Sample, writing for The Guardian, noted that, "Positive psychologists also stand accused of burying their heads in the sand and ignoring that depressed, even merely unhappy people, have real problems that need dealing with." Sample also quoted Steven Wolin, a clinical psychiatrist at George Washington University, as saying that the study of positive psychology is just a reiteration of older ways of thinking, and that there is not much scientific research to support the efficacy of this method. Gable responds to criticism on their pollyanna view on the world by saying that they are just bringing a balance to a side of psychology that is glaringly understudied. To defend his point, Gable points to the imbalances favouring research into negative psychological wellbeing in cognitive psychology, health psychology, and social psychology.
Barbara Held argued that while positive psychology makes contributions to the field of psychology, it has its faults. She offered insight into topics including the negative side effects of positive psychology, negativity within the positive psychology movement, and the current division in the field of psychology caused by differing opinions of psychologists on positive psychology. In addition, she noted the movement's lack of consistency regarding the role of negativity. She also raised issues with the simplistic approach taken by some psychologists in the application of positive psychology. A "one size fits all" approach is arguably not beneficial to the advancement of the field of positive psychology; she suggested a need for individual differences to be incorporated into its application.
Martin Jack has also maintained that positive psychology is not unique in its optimistic approach to looking at optimal emotional wellbeing, stating that other forms of psychology, such as counselling and educational psychology, are also interested in positive human fulfillment. He goes on to mention that, while positive psychology has pushed for schools to be more student-centred and able to foster positive self-images in children, he worries that a lack of focus on self-control may prevent children from making full contributions to society. 
... Amongst psychologists ... the importance of promoting health rather than simply preventing ill-health date back to the 1950s (Jahoda, 1958)